The 1962 Survey of Noise and Loss on Toll Connections

Abstract

The 1962 sample survey of message circuit noise and loss on Bell System toll connections is described and discussed in this article. The results are presented in terms of the distribution of noise levels on toll calls as established in the present system, the distribution of end-office to end-office losses on these calls, and the distribution of airline distances between end-offices. It is shown that the noise distribution referred to the subscriber's set has a mean of 19.7 dbrnc with a standard deviation of 7.8 db, that the mean of the distribution of end-office to end-office losses is 7.7 db with a standard deviation of 3.0 db, and that 50 per cent of all toll calls are shorter than 30 miles, while only 10 per cent span a distance of more than 250 miles. The noise level versus distance and loss versus distance relationships are investigated and analyzed. The noise level is found to increase by 2.2 db for each doubling of the airline distance between end-offices, while the loss shows an increase of 0.6 db for each doubling of the distance. Finally, present performance of the Bell System toll plant is evaluated in terms of noise and volume grade-of-service estimates.